#include <bits/stdc++.h>
#define int long long
#define P(x) do {if(debug) cout << x << endl;} while(false)
#define H(x) P(#x << ": " << x)
#define FR(i, a, b) for(int i = (a); i < (b); ++i)
#define F(i, n) FR(i, 0, n)
#define DR(i, a, b) for(int i = (b); i --> (a);)
#define D(i, n) DR(i, 0, n)
#define S(s) (int)(s).size()
#define ALL(x) (x).begin(), (x).end()
#define MI(x, a) (x) = min(x, a)
#define MA(x, a) (x) = max(x, a)
#define V vector
#define pb push_back
#define mp make_pair
using namespace std;
const bool debug = 1;
int N,M,D;
vector<pair<int, int> > jobs;
bool possible(int A, bool bol){
queue<pair<int,int> > q;
int i = 0;
F(d,N){
if(!q.empty()&&q.front().first<d){
return false;
}
while(i<M&&jobs[i].first==d){
q.push({d+D,jobs[i].second});
i++;
}
for(int j = 0; j < A && !q.empty(); j++){
if(bol){
cout<<q.front().second+1<<" ";
}
q.pop();
}
if(bol){
cout<<0<<endl;
}
}
return true;
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cin>>N>>D>>M;
jobs.resize(M);
F(i, M){
cin>>jobs[i].first;
jobs[i].second=i;
jobs[i].first--;
}
sort(jobs.begin(), jobs.end());
int res = 0;
for(int bs = 1<<23; bs>=1; bs>>=1){
if(!possible(res|bs, false)){
res|=bs;
}
}
res++;
cout<<res<<endl;
possible(res, true);
return 0;
}
